Set mail attachment size limit?

Is there a way to apply an attachment size limit to exim/smtp for 1.) outgoing mail in general, and 2.) mail sent to (cPanel-defined list) list recipients.

Problem: A customer of mine sent an e-mail w/ a 42MB (!!!) attachment to a list of 11 recipients (all recipient mailboxes on the same server), which sent qrunner into a tizzy. We finally got that straightened out and advised the customer. Later, someone else there sent 11 individual messages containing the same attachment to the same recipients.

Would like to have a situation where the server just says "no" to large attachments anyone attempts to send.